On Thu, Apr 11, 2024, 5:55 PM Richard Henderson <richard.hender...@linaro.org> wrote: > > On 4/11/24 14:29, M Bazz wrote: > > fixes a longstanding bug which causes a "Nonparity Synchronous Error" > > kernel panic while using a debugger on Solaris / SunOS systems. The panic > > would occur on the first attempt to single-step the process. > > > > The problem stems from an lda instruction on ASI_USERTXT (8). This asi > > was not being resolved correctly by resolve_asi(). > > > > Further details can be found in #2281 > > > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2281 > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2059 > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1609 > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1166 > > > > Signed-off-by: M Bazz <b...@bazz1.com> > > --- > > target/sparc/translate.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/target/sparc/translate.c b/target/sparc/translate.c > > index 319934d9bd..1596005e22 100644 > > --- a/target/sparc/translate.c > > +++ b/target/sparc/translate.c > > @@ -3,6 +3,7 @@ > > > > Copyright (C) 2003 Thomas M. Ogrisegg <t...@fnord.at> > > Copyright (C) 2003-2005 Fabrice Bellard > > + Copyright (C) 2024 M Bazz <b...@bazz1.com> > > > > This library is free software; you can redistribute it and/or > > modify it under the terms of the GNU Lesser General Public > > @@ -1159,6 +1160,7 @@ static DisasASI resolve_asi(DisasContext *dc, int > > asi, MemOp memop) > > || (asi == ASI_USERDATA > > && (dc->def->features & CPU_FEATURE_CASA))) { > > switch (asi) { > > + case ASI_USERTXT: /* User text access */ > > case ASI_USERDATA: /* User data access */ > > mem_idx = MMU_USER_IDX; > > type = GET_ASI_DIRECT; > > I don't believe this is correct, because it operates against the page's > "read" permissions > instead of "execute" permissions. > > > r~
Hi Richard, Thanks for your guidance. It set me in the right direction. Now I think I've got the right spot. function `helper_ld_asi` has a block to help load ASI_KERNELTXT, but the ASI_USERTXT case defaults to sparc_raise_mmu_fault(); I believe this is the true culprit source reference: https://gitlab.com/qemu-project/qemu/-/blob/master/target/sparc/ldst_helper.c?ref_type=heads#L687 The code for the ASI_KERNELTXT seems generic enough to also use for ASI_USERTXT verbatim. See v2 patch below. I've done a `make test` -- all passing (3 skips). OS boots, and the debuggers are working without issue. What do you think? Once we arrive at the right solution, I'll finalize the patch. -bazz diff --git a/target/sparc/ldst_helper.c b/target/sparc/ldst_helper.c index e581bb42ac..4f87e44a93 100644 --- a/target/sparc/ldst_helper.c +++ b/target/sparc/ldst_helper.c @@ -684,6 +684,7 @@ uint64_t helper_ld_asi(CPUSPARCState *env, target_ulong addr, case ASI_M_DIAGS: /* Turbosparc DTLB Diagnostic */ case ASI_M_IODIAG: /* Turbosparc IOTLB Diagnostic */ break; + case ASI_USERTXT: /* User code access */ case ASI_KERNELTXT: /* Supervisor code access */ oi = make_memop_idx(memop, cpu_mmu_index(env_cpu(env), true)); switch (size) { @@ -779,7 +780,6 @@ uint64_t helper_ld_asi(CPUSPARCState *env, target_ulong addr, case 0x4c: /* SuperSPARC MMU Breakpoint Action */ ret = env->mmubpaction; break; - case ASI_USERTXT: /* User code access, XXX */ default: sparc_raise_mmu_fault(cs, addr, false, false, asi, size, GETPC()); ret = 0;
